Peterson 6.5cr Brass

[Skeller185]

1st post on the forum and welcome any comments. Great information on these forums and as a newbie to long range and reloading, appreciate all the knowledge to tap into out there.

Just received some new Peterson 6.5cr brass and ran some tests today. Load history all based of Lapua load development to make comparison. Load data was mid node for my rifle using Lapua brass, 42.6g of H4350and CCI 450 primers. Lapua brass ran 2700fps velocity and very accurate. No pressure signs whatsoever. Ran same load in Peterson brass....2730fps but resulted in high pressure with heavy bolt lift with some wipe on the case. This was brass 1st firing but unsure why moderate load and velocity would show pressure signs between the two different brass. All brass fl sized, trimmed, deburred before loading.

Comments welcome!

 

[Skeller185]

For Optimal Performance You May Need To Change Your Load
https://www.petersoncartridge.com/about/technical-articles/78-change-your-load

A change in internal volume will change the performance of your load, and potentially your results at the target. The internal volume of Winchester casings is different than Hornady, which is different from Lapua, which is different than Norma, which is different from ours. This means that the load you worked up to use in Lapua casings, for example, might not be optimal for Peterson casings, and vice versa.

The internal volume of Peterson casings is slightly less than some of the other casing manufacturers. This results in increased velocities. Once shooters re-work their load for optimal performance in our casings, they usually find they can achieve tighter groups than from the other casings they used. A common finding our customers report is, “Same gun, same bullet, cut my group size in half with Peterson casings.” But frequently this takes re-working their load.

Along those lines Jack M. reported, “After reloading about 20 rounds of Peterson brass along with another manufacturer’s brass, we headed to the range. After a few shots we noted the Peterson rounds were consistently impacting about .75 to 1” higher than the other brass. Nice tight group, just higher. Confused by the difference, we set up our chronograph and found that using the same powder, bullet and die setting, we were constantly getting 90 to 100 fps more than with the other brass. The Peterson brass showed no evidence of overcharge. Nice surprise, more velocity without increasing the powder charge.”

Another customer, Bryan J., had a similar story to tell. He reported that using the same load he used for our competitor’s casings, the results he got with Peterson cases were erratic. At first he thought maybe it was his gun. So he tried a second gun, with the same results. Now thinking it could be a difference in internal volume he worked up a new load for the Peterson cases. Then he got these results from 5-shot groups at 100 yards:

• Competitor’s factory load = .89”
• Competitor once-fired = .72”
• Peterson brass out of the box = .44”

The point of all this? Since rifle casings from different manufacturers have different internal volumes, you may need to change your load, to optimize your performance when using casings from a different manufacturer.

Here is the puzzling part. I did a case volume comparison between the Peterson and Lapua. The Peterson was certainly less. My pet load running the 140 ELD M is 43.2g of H4350. This gets me very consistent 2750fps and sub moa. With less case volume, I dropped the charge down to the 42.6g as a test. Considering velocity was 2730fps with pressure signs, I will have to drop charge which will result in lower velocity. Should I take this initial data and assume I will have to settle for lower velocity overall with the Peterson brass?

 

[MarinePMI]

Small primered CM brass is well known to have slightly lower velocities to begin with, and with the smaller case capacity, you may very well have to settle for an even (slightly) lower velocity.

I haven't seen anyone do it (which doesn't someone hasn't), but I'd wager the smaller case capacity and primer may warrant a different powder all together (like Re17 or Varget). Anyone know off thetop of their head the case volume of a 6.5x47, and if it's close to these newer 6.5CM cases?

I think people just assume H4350 will work well in all 6.5 CM brass, but with the smaller case capacity/primer brass, I'd wager the ignition and burn rate have changed enough that another powder is warranted for optimum velocity and pressure.

Just a thought...

 

[Lesco Brandon]

In my small rifle primer Pedersen brass I’m loading 41.8g H4350 and pushing them at 2750 FPS. I have loaded up 47.7g of R26 and got 2925 FPS with SD of 9 in the same brass. I will say that from using Hornady, lapua, and Pedersen brass I believe the Pedersen pockets loosen up quicker then lapua. After one hot load some pockets felt loose whereas I’m on my 4th firing of lapua with no signs.
Cci br primers

 

[Lesco Brandon]

Small primered CM brass is well known to have slightly lower velocities to begin with, and with the smaller case capacity, you may very well have to settle for an even (slightly) lower velocity.

I haven't seen anyone do it (which doesn't someone hasn't), but I'd wager the smaller case capacity and primer may warrant a different powder all together (like Re17 or Varget). Anyone know off thetop of their head the case volume of a 6.5x47, and if it's close to these newer 6.5CM cases?

I think people just assume H4350 will work well in all 6.5 CM brass, but with the smaller case capacity/primer brass, I'd wager the ignition and burn rate have changed enough that another powder is warranted for optimum velocity and pressure.

Just a thought...

Greetings! While the size of the primer would logically lead one to believe bigger is better, lapua specifically designed their case to maximize the flash column using a small primer and an undersized flash hole.
I’ve used lapua brass, pederson brass, and Hornady with the same powders (H4350, R16, R17, H4831sc, varget, R26, and Superformance) and was unable to achieve a notable increase in velocity with Hornady brass. Using compressed loads a full 2 grains over pederson capacity only gained me 30fps using R26 but the SD was horrible. Anecdotally I see small primer pockets being able to handle warmer loads better.
Cheers.

 

[MarinePMI]

Anecdotally I see small primer pockets being able to handle warmer loads better.
Cheers.

I would hope so, since that is the intent of small primer pocket brass; stronger, longer lasting case life.

 

[Skeller185]

By water weight, the Peterson was 1.5 gn less than the Lapua brass, on average. I have to say the weight spread with the Peterson was considerably higher than the Lapua with a 5-6 gn spread through 100 pcs from same lot. Not what I was expecting considering reviews I read but not a deal breaker.

I thought the 42.6gn of H4350 would be a safe start point just for a test. Considering the resulting velocity, looks like I have to go to lighter loads for development. Currently, I shoot 140gn nearly 100% of the time but always looking for a bit more velocity since I shoot in the Nevada desert. Rarely a time with no wind so for longer ranges, 800-1000yd, I thought the added velocity would work in my favor. With my current 2740 fps range I am at, it has been working pretty well.

Not sure why but from what I have read, the Tikka Tac A1 6.5cm (24" factory barrel) are not know for their high velocity in the heavier bullets.

That's another question from a newbie...how hard should I chase velocity?